1. Field of the Invention
The present invention relates to an interconnect substrate for a semiconductor assembly and a method of making the same, and more particularly to an interconnect substrate with embedded semiconductor device and built-in stopper and a method of making the same.
2. Description of Related Art
As market trend demands for thinner, smarter and cheaper portable electronics, semiconductor devices for use in these equipments are required to further shrink their size and improve electrical performances at lower cost. Among all the efforts, embedding or built-in semiconductor chip in printed wiring board to form a module assembly is considered the most effective approach since it can drastically reduce the overall weight, thickness and improve electrical performance through a shorten interconnect distance.
However, the attempt of embedding chip in a wiring board can encounter many problems. For example, the chip to be embedded is known to vertically and laterally shift during die attach and encapsulation/lamination processes due to thermal characteristics of plastic materials. The CTE mismatch between metal, dielectric and silicon at various stages of thermal treatment can result in misalignment of the build-up interconnect structure to be deposited thereon. U.S. Pat. No. 7,935,893 to Tanaka et. al., U.S. Pat. No. 7,944,039 to Aral and U.S. Pat. No. 7,405,103 to Chang disclose various alignment methods to address manufacturing yield concern. None of these approaches offers a proper solution or effective method for controlling die movement because the underneath adhesive will reflow during curing and therefore dislocates the attached die from the pre-determined location even a highly precise alignment mark and equipment are applied. U.S. Patent Application 2010/0184256 to Chino discloses a resin sealing method to fix the semiconductor device adhered to the adhesive layer formed on the support body. This approach may be effective in controlling die from further movement during sealing process, it does not provide any control or adjustment for die attach process and the mis-registration is unavoidable due to die attach adhesive reflows.